Largely paralleling research on general homicides, research on the structural covariates of murders of police has been carried out at various levels of areal aggregation. However, although the general homicide research has been extended to counties in the United States, research on murders of police has yet to follow suit. To begin to fill this gap, this study extends research on the structural covariates of police homicides to the county level. Controlling for the number of law enforcement officers at risk, we find that police were more likely to be murdered in economically depressed counties and in counties with larger percentages of African Americans, persons aged 25 to 34, and nonsheriff agencies. Police homicide risk was significantly lower in urbanized counties and in counties located in the Northeast, whereas the South was no riskier than the West or Midwest. Murders of police were unrelated to population mobility, divorce, and levels of violent crime.